Shearing machine

ABSTRACT

A drive cutter blade and a backing cutter blade are mounted in a frame and relatively movable toward and away from each other to cut through a workpiece disposed between them. An eccentric drive mechanism is connected to said driven cutter blade and operable to perform alternating cutting strokes in the direction from said driven cutter blade toward said backing cutter blade and return strokes in the direction from said backing cutter blade toward said driven cutter blade. Said cutter blades are adapted to be spaced apart a distance which exceeds the extent of one of said strokes. One of said cutter blades is a follow-up cutter blade. Follow-up drive means are connected to said follow-up cutter blade and adapted to impart to said follow-up cutter blade a follow-up movement toward the other cutter blade during each of said return strokes. Said follow-up drive means comprise a hydraulic actuator connected to said follow-up cutter blade, a hydraulic supply conduit connected to said actuator and adapted to supply liquid under pressure thereto in the direction of said follow-up movement, a shut-off valve incorporated in said conduit, and means for closing said shut-off valve during said working strokes to block the supply of liquid to said actuator and for opening said shut-off valve during said return strokes to permit of a supply of liquid to said actuator A workpiece having a thickness exceeding the extent of one of said strokes can thus be cut through in a plurality of cutting strokes and both said cutter blades remain in contact with said workpiece during said return strokes.

United States Patent [1 1 Scherb et al.

1451 July 17, 1973 I SHEARING MACHINE [75] Inventors: Gustav Scherb,Linz; Norbert Auer,

Traun, both of Austria Vereinigte Osterreichische Eisen-und StahlwerkeAktiengesellschaft, Linz, Austria 22 Filed: July 23,1971

211 App]. No.: 165,454

[73] Assignee:

[30] Foreign Application Priority Data Primary Examiner-Andrew R..luhasz Assistant Examiner-W. D. Bray Attorney-Kurt Kelman [57] ABSTRACTA drive cutter blade and a backing cutter blade are mounted in a frameand relatively movable toward and away from each other to cut through aworkpiece disposed between them. An eccentric drive mechanism isconnected to said driven cutter blade and operable to performalternating cutting strokes in the direction from said driven cutterblade toward said backing cutter blade and return strokes in thedirection from said backing cutter blade toward said driven cutterblade. Said cutter blades are adapted to be spaced apart a distancewhich exceeds the extent of one of said strokes. One of said cutterblades is a follow-up cutter blade. Follow-up drive means are connectedto said foll0w-up cutter blade and adapted to impart to said follow-upcutter blade a follow-up movement toward the other cutter blade duringeach ofsaid return strokes. Said follow-up drive means comprise ahydraulic actuator connected to said follow-up cutter blade, a hydraulicsupply conduit connected to said actuator and adapted to supply liquidunder pressure thereto in the direction of said follow-up movement, ashutoff valve incorporated in said conduit, and means for closing saidshut-off valve during said working strokes to block the supply of liquidto said actuator and for opening said shut-off valve during said returnstrokes to permit of a supply of liquid to said actuator A workpiecehaving a thickness exceeding the extentof one of said strokes can thusbe cut through in a plurality of cutting strokes and both said cutterblades remain in contact with said workpiece during said return strokes.

6 Claims, 4 Drawing Figures PAIENItD l 3. 745.867

sum 1 BF 2 FIG] 7 SHEARING MACHINE This invention relates to a shearingmachine for cutting through thick metallic workpieces, such as ingots,slabs, billets or the like, in a plurality of closely succeeding cuttingstrokes, which machine comprises two cutter blades, which are mounted ina frame and one of which is movable by means of a crank drive toward theother cutter blade, which is stationary at least during the cuttingstrokes, said one cutter blade performing cutting strokes and returnstrokes in alternation, and one of the cutter blades being displaceableduring the return strokes by a follow-up drive toward the other cutterblade by a distance which corresponds to the stroke.

In order to avoid as far as possible a deformation of the workpieceduring the cut, such shears use a small or zero cutting angle. Owing tothis small cutting angle, large cutting forces are required. When it isdesired to cut through the workpiece in a single stroke, mechanicalshears driven by a crank drive must exert a high driving torque,depending on the thickness of the workpiece. This involves the need fora drive means having large dimensions.

Shearing machines have already been disclosed in which the cutter bladesare driven by a crank drive and in which the driving torque requirementis reduced in that said cutter blades cut through the workpiece in aplurality of closely succeeding strokes rather than in a single cuttingstroke. A follow-up movement is imparted to one of the two cutter bladesby a screw during the return stroke in such a manner that both cutterblades constantly engage the workpiece. Hence, one cutter blade isadvanced during the return stroke toward the other cutter blade to theextent of the return stroke so that the next shear cut is effectedduring the next working stroke of the crank. That known stepwisefollow-up movement of the cutter blades has various drawbacks. Aseparate drive motor is required to rotate the screw, and this motormust be very strong to overcome the frictional forces between the screwand the nut moving thereon and to move all heavy masses, such as thecutter blades, the cutter blade holder, etc. On the other hand, thedrive must be sufficiently strong to retract the cutter blades when themachine is jammed. Because the screw itself is a rigid connectingelement and cannot yield in the case of trouble to protect the shearsfrom damage, particularly near the dead center positions of the crankmotion, a separate low-strength member or the like must be provided toprevent such damage.

It is an object of the invention to eliminate these disadvantages and toprovide a shearing machine which enables a follow-up movement of one ofthe two cutter blades with simple means and with a low power requirementwhereas the risk of damage to the machine when it is jammed iseliminated.

In a shearing machine of the kind defined first hereinbefore, the aboveobject is accomplished by the invention essentially in that theadditional drive consists of a hydraulic actuator, which is providedwith a hydraulic supply conduit incorporating a shut-off valve which isadapted to be operated in synchronism with the cycles of the cutterblades to shut off said conduit. During the return stroke of the crankdrive, the shut-off valve opens the hydraulic supply conduit to supplythe cylinder of the actuator so that additional liquid under pressurecan enter the cylinder and the cutter blade connected to the actuator isadvanced toward the other cutter blade and thus remains in engagementwith the workpiece. During the cutting stroke, the shutoff valve isclosed. The hydraulic actuator serves as a rigid connector and the nextcut is effected.

If, in accordance with the invention, pressue is applied to both ends ofthe actuator to retract the cutter blade, the cutter blade connected tothe actuator can be returned in a simple manner to its starting positionfor a new cut.

To enable a taking up of any forces which might damage the shearingmachine, it is a further feature of the invention to connect thecylinder of the actuator to an adjustable pressure relief valve, whichwill open when the pressure applied to the actuator exceeds the pressureto which the valve has been set. Pressure fluid can now escape from thecylinder and the piston is displaced in the cylinder until the pressurehas been reduced to the value to which the pressure relief valve hasbeen set.

A plurality of embodiments of the invention are shown by way of examplein the drawings, in which FIGS. 1, 2, and 3 are diagrammaticlongitudinal sectional views showing respective embodiments of shearingmachines according to the invention, and

FIG. 4 is a diagrammatic representation of the hydraulic system forcontrolling the actuator.

Two cutter blades 2 and 3 are mounted in a frame I. The cutter'blade 2is driven by a crank drive consisting of a connecting rod 4 and aneccentric shaft 5. In FIGS. 1 and 2, the cutter blade and in FIG. 3 thecutter blade 3 is connected to a hydraulic actuator. In FIGS. 1 and 2,that actuator is connected between the crank drive and the cutter blade2, and the cutter blade 3 is firmly mounted in the frame 1. In FIG. 3,the cutterblade 3 is moved by the actuator, which bears on the frame I.The cylinder 6 of the actuator may be formed by the connecting rod 4itself, as is shown in FIG. 1, or may be pivoted to the connecting rod4, as is shown in FIG. 2. If the cylinder 6 is formed by the connectingrod 4, the piston rod of the piston 7 must be mounted in aball-and-socket joint in the holder for the cutter blade 2.

The cylinder 6 is connected to a hydraulic supply conduit 8, which canbe shut off by a shut-off valve 9. The shut-off valve 9 can becontrolled by means of a pilot conduit 10 in synchronism with thestrokes of the crank drive 4, 5 to open and close the supply conduit 8.Another hydraulic conduit 11 is connected to the cylinder 6 on the otherside of the piston 7, and liquid under pressure can be pumped into thecylinder 6 when the shut-off valve 9 is open. A pressure relief valve 12is connected to the conduit 8 between the cylinder 6 and the shut-offvalve 9, and a conduit leads from the pressure relief valve 12 to apressure fluid reservoir 13.

When the crank drive performs a cutting stroke, the shut-off valveincorporated in the supply conduit'8 is closed and the actuator piston7is held in position. The driving force of the crank drive is. thendirectly transmitted to the cutter blade 2. When the crank drive reachesits dead center position, a limit switch, not shown, is operated tocause the shut-off valve 9 to open so that the supply pump can supplyliquid to the piston 7 of the actuator as long as the pressure to whichthe pressure relief valve 12 has been set is not exceeded. The cutterblade which has been connected to the hydraulic actuator is now advancedtoward the other cutwith the workpiece. When the crank drive reaches itsother dead center position, another limit switch is operated to causethe shut-off valve 9 to close so that another cutting stroke can beperformed. In the case of trouble, e.g., when a cutter blade remainsstuck in the workpiece, the shearing machine will not be damaged becausethe pressure relief valve 12 opens automatically when the set maximumupper pressure limit is exceeded and the piston in the cylinder of theactuator can then yield. Because liquid pressure can be applied to theother end of the hydraulic piston through the conduit 11, the cutterblade can be withdrawn out of the workpiece in the case of a failure ofthe main drive. The possibility to apply pressure to both ends of thepiston 7 of the actuator enables a movement of the piston in bothdirections. This is also desirable for the restoring of the actuator toits initial position for a new cut.

We claim:

1. In a shearing machine which comprises a frame, a driven cutter bladeand a backing cutter blade mounted in the frame and defining a gaptherebetween for receiving a workpiece to be severed, an eccentric drivemechanism connected to the driven cutter blade and operable to performalternating cutting and return strokes, the driven cutter blade beingmoved incrementally into the gap during each of the cutting strokestoward the backing cutter blade to cut the workpiece, the backing cutterblade being arranged to be held stationary relative to the frame duringthe cutting strokes, and a follow-up drive means connected to one of thecutter blades to impart to the one cutter blade a follow-up movement inrespect of the other cutter blade during each of the return strokes andcorresponding substantially to the extent of the return stroke to keepthe gap between the cutter blades substantially unchanged during thereturn strokes, the improvement of the followup drive meanscomprising 1. hydraulic actuator connected to the one cutter blade,

2. a hydraulic supply conduit connected to the actuator and arranged tosupply hydraulic fluid under pressure thereto for operating the actuatorto move the one cutter blade in the direction of the followup movement,

3. a shut-ofl valve mounted in the hydraulic supply conduit, and

4. means for closing the shut-off valve during the cutting strokes toblock the supply of hydraulic fluid to the actuator and for opening theshut-off valve during the return strokes to supply the fluid to theactuator for operating the same.

2. In the shearing machine of claim I, a second hydraulic supply conduitconnected to the actuator and arranged to supply hydraulic fluid underpressure thereto for operating the actuator to move the one cutter bladein a direction opposite to that of the follow-up movement whereby theone cutter blade is retracted from the other cutter blade.

3. In the shearing machine of claim 1, an adjustable pressure reliefvalve arranged in the hydraulic supply conduit between the actuator andthe shut-off valve.

4. In the shearing machine of claim I, the one cutter blade being thedriven cutter blade and the hydraulic actuator being mounted between theeccentric drive mechanism and the driven cutter blade, the actuatorconnecting the drive mechanism to the driven cutter blade.

5. In the shearing machine of claim 1, the one cutter blade being thebacking cutter blade.

6. In a machine for applying pressure to a workpiece, which comprises aframe, a driven pressure-applying member and a backing pressure-applyingmember mounted in the frame and defining a gap therebetween forreceiving the workpiece, an eccentric drive mechanism connected to thedriven pressure-applying member and operable to perform alternatingpressureapplying working strokes and return strokes, the drivenpressure-applying member being moved incrementally into the gap duringeach of the working strokes toward the backing pressure-applying member,the backing pressure-applying member being arranged to be heldstationary relative to the frame during the working strokes, and afollow-up drive means connected to one of the pressure-applying memberto impart to the one pressure-applying member a follow-up movement inrespect of the other pressure-applying member during each of the returnstrokes and corresponding substan tially to the extent of the returnstroke to keep the gap between the pressure-applying memberssubstantially unchanged during the return strokes, the improvement ofthe follow-up drive means comprising 1. a hydraulic actuator connectedto the one pressure-applying member,

2. a hydraulic supply conduit connected to the actuator and arranged tosupply hydraulic fluid under pressure thereto for operating the actuatorto move the one pressure-applying member in the direction of thefollow-up movement,

3. a shut-off valve mounted in the hydraulic supply conduit, and

4. means for closing the shut-off valve during the working strokes toblock the supply of hydraulic fluid to the actuator and for opening theshut-off valve during the return strokes to supply the fluid to theactuator for operating the same.

I t t

1. In a shearing machine which comprises a frame, a driven cutter bladeand a backing cutter blade mounted in the frame and defining a gaptherebetween for receiving a workpiece to be severed, an eccentric drivemechanism connected to the driven cutter blade and operable to performalternating cutting and return strokes, the driven cutter blade beingmoved incrementally into the gap during each of the cutting strokestoward the backing cutter blade to cut the workpiece, the backing cutterblade being arranged to be held stationary relative to the frame duringthe cutting strokes, and a follow-up drive means connected to one of thecutter blades to impart to the one cutter blade a follow-up movement inrespect of the other cutter blade during each of the return strokes andcorresponding substantially to the extent of the return stroke to keepthe gap between the cutter blades substantially unchanged during thereturn strokes, the improvement of the follow-up drive meanscomprising
 1. hydraulic actuator connected to the one cutter blade,
 2. ahydraulic supply conduit connected to the actuator and arranged tosupply hydraulic fluid under pressure thereto for operating the actuatorto move the one cutter blade in the direction of the follow-up movement,3. a shut-off valve mounted in the hydraulic supply conduit, and 4.means for closing the shut-off valve during the cutting strokes to blockthe supply of hydraulic fluid to the actuator and for opening theshut-off valve during the return strokes to supply the fluid to theactuator for operating the same.
 2. a hydraulic supply conduit connectedto the actuator and arranged to supply hydraulic fluid under pressurethereto for operating the actuator to move the one cutter blade in thedirection of the follow-up movement,
 2. In the shearing machine of claim1, a second hydraulic supply conduit connected to the actuator andarranged to supply hydraulic fluid under pressure thereto for operatingthe actuator to move the one cutter blade in a direction opposite tothat of the follow-up movement whereby thE one cutter blade is retractedfrom the other cutter blade.
 2. a hydraulic supply conduit connected tothe actuator and arranged to supply hydraulic fluid under pressurethereto for operating the actuator to move the one pressure-applyingmember in the direction of the follow-up movement,
 3. a shut-off valvemounted in the hydraulic supply conduit, and
 3. In the shearing machineof claim 1, an adjustable pressure relief valve arranged in thehydraulic supply conduit between the actuator and the shut-off valve. 3.a shut-off valve mounted in the hydraulic supply conduit, and
 4. meansfor closing the shut-off valve during the cutting strokes to block thesupply of hydraulic fluid to the actuator and for opening the shut-offvalve during the return strokes to supply the fluid to the actuator foroperating the same.
 4. In the shearing machine of claim 1, the onecutter blade being the driven cutter blade and the hydraulic actuatorbeing mounted between the eccentric drive mechanism and the drivencutter blade, the actuator connecting the drive mechanism to the drivencutter blade.
 4. means for closing the shut-off valve during the workingstrokes to block the supply of hydraulic fluid to the actuator and foropening the shut-off valve during the return strokes to supply the fluidto the actuator for operating the same.
 5. In the shearing machine ofclaim 1, the one cutter blade being the backing cutter blade.
 6. In amachine for applying pressure to a workpiece, which comprises a frame, adriven pressure-applying member and a backing pressure-applying membermounted in the frame and defining a gap therebetween for receiving theworkpiece, an eccentric drive mechanism connected to the drivenpressure-applying member and operable to perform alternatingpressure-applying working strokes and return strokes, the drivenpressure-applying member being moved incrementally into the gap duringeach of the working strokes toward the backing pressure-applying member,the backing pressure-applying member being arranged to be heldstationary relative to the frame during the working strokes, and afollow-up drive means connected to one of the pressure-applying memberto impart to the one pressure-applying member a follow-up movement inrespect of the other pressure-applying member during each of the returnstrokes and corresponding substantially to the extent of the returnstroke to keep the gap between the pressure-applying memberssubstantially unchanged during the return strokes, the improvement ofthe follow-up drive means comprising